Anybody? I would really like to complete a migration to Stretch and 4.14 due to the awesomeness of uBoot overlays and the pre-built overlay-root setup that is available from a setting in uEnv.txt, that’s a big help for my project.
Hugh - I’m a real newbie. I compiled a device tree overlay with not errors and have a dtbo file now. I just don’t know how to get it into the boot process. Where do I put it, do I need to change a file like env.txt somewhere to get it to load and if so what syntax do i use? Where did you find these instructions? I’m so lost and need to keep moving forward. it was going so well…
There are some obvious places in /boot/uEnv.txt. If it doesn’t load though, usually the only way you can debug is to hook up a serial console to UART0 because uboot loads before kernel logging starts.
Hi Walter, I’m afraid I can’t help with your custom device overlay issue, it us really a topic for a new thread in the uBoot section I would have thought?
I would be interested in hearing how you compiled a custom device tree overlay though. We have our BBB on a custom card that uses a bunch of gpio, an eqep module, a bunch of uarts and some pru_ecap pwm - it’s a lot of work for config-pin to setup at boot time and I’d like to trim this 13 seconds of work out of my bootup if possible. Perhaps you could make a post in the uBoot section?
Hugh - I’ll dig around in the UBoot section. Thanks for suggesting that. I’m such a newbie on here!
As for how I compiled the custom device tree overlay, I followed the instructions posted at this location and it worked fine - no errors after I corrected the typos, etc. that were posted in the comments.
I’d really like to get this temperature sensor working but all the instructions are pre-Uboot. I can make a lot of progress with my prototype once I get this working but liquid temperature is a critical input so without it I can’t move forward!
If you can live with using the universal-cape and just configuring the pins once booted using the config-pin utility, that’s a good way to go. What programming language are you wanting to use to write your temperature sensor software? If you are doing it from the PRU then you can just code up your own i2c read function and access the registers directly though the memory map, just like any standard MCU.
I plan to write the code in C since I’m most familiar with it (although very rusty, but it’s coming back) and I have considered learning Python and using it.
By the way, thanks to all for your patience with me on this! It has been a long time since I worked in this space and a lot has changed and improved!
Our application is node.js for the easy stuff with all the heavy lifting done in the PRU… if you want to code in C, it’s worth looking at the MRAA libraries from Intel https://github.com/intel-iot-devkit/mraa
I think it is related to uboot overlays. I started a new thread over in the uBoot section... You might like to take a look over there, Robert has posted an image for me to try but perhaps you can test it for me? I'm currently sd-card-writer-less...
